1. Field of the Invention
This invention relates to a water-repellent detergent, especially suited as a water-repellent window wash liquid for automobiles.
2. Prior Art
Water-repellent detergents as typified by water-repellent window wash liquids for automobiles are commercially available as automotive chemical parts. Such wash liquids function not only to clean windshields, but also to impart water repellency thereto. Commercial products include Linda by Yokohama Yushi K. K., Glaco Washer Liquid by Soft 99 K. K., and Amenbo Washer by CCI K. K. Since these water-repellent window wash liquids contain polydimethylsiloxane, polymethylphenylsiloxane or amino-modified siloxane as a water-repellent component, they spread water-repellent films which form little or very weak chemical bond with the surface of a substrate to be cleaned and hence, do not durably last. Also the initial water repellency is weak since the basic skeleton of such siloxane is a hydrocarbon chain.
JP-A 179850/1995 discloses a wash liquid comprising a product resulting from hydrolysis of a fluoroalkylsilane with hydrochloric acid or nitric acid. Its initial water repellency is enough since the water-repellent component is a fluoroalkyl group. However, the wash liquid is less stable since the hydrolysate of fluoroalkylsilane is essentially water insoluble. The use of strong acid such-as hydrochloric acid and nitric acid leaves a possibility that rubber blades and painted surfaces of wipers be damaged or corroded.